Add (failing) test for #3194

Author: cowtowncoder

src/test/java/com/fasterxml/jackson/failing/PolymorphicArrays3194Test.java

@@ -0,0 +1,49 @@
+package com.fasterxml.jackson.failing;
+
+import com.fasterxml.jackson.databind.BaseMapTest;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.ObjectMapper.DefaultTyping;
+import com.fasterxml.jackson.databind.json.JsonMapper;
+import com.fasterxml.jackson.databind.jsontype.BasicPolymorphicTypeValidator;
+import com.fasterxml.jackson.databind.jsontype.PolymorphicTypeValidator;
+
+// [databund#3194]: Discrepancy between Type Id inclusion on serialization vs
+// expectation during deserialization causes mismatch and fails deserialization.
+public class PolymorphicArrays3194Test extends BaseMapTest
+{
+    static final class SomeBean {
+        public Object[][] value;
+    }
+
+    public void testTwoDimensionalArrayMapping() throws Exception
+    {
+        PolymorphicTypeValidator typeValidator = BasicPolymorphicTypeValidator.builder()
+                .allowIfSubTypeIsArray()
+                .allowIfSubType(Object.class)
+                .build();
+
+        ObjectMapper mapper = JsonMapper
+                .builder()
+                .activateDefaultTyping(typeValidator, DefaultTyping.NON_FINAL)
+                .build();
+
+        SomeBean instance = new SomeBean();
+        instance.value = new String[][]{{"1.1", "1.2"}, {"2.1", "2.2"}};
+        String json = mapper
+//                .writerWithDefaultPrettyPrinter()
+                .writeValueAsString(instance);
+        
+        // Note: we'll see something like:
+        // 
+//  {
+//    "value" : [ "[[Ljava.lang.String;", [ [ "[Ljava.lang.String;", [ "1.1", "1.2" ] ], [ "[Ljava.lang.String;", [ "2.1", "2.2" ] ] ] ]
+//  }
+
+     // that is, type ids for both array levels.   
+        
+// System.err.println("JSON:\n"+json);        
+        SomeBean result = mapper.readValue(json, SomeBean.class); // fails
+        assertEquals(String[][].class, result.value.getClass());
+        assertEquals(String[].class, result.value[0].getClass());
+    }
+}